YA Fantasy- girl finds an alternative universe's version of herself online. when they meet & hands touch she is transported to this girls parallel universe [s]

[Gracie]

So I read this book probably about five years ago, and can remember a fair bit of it and yet have never been able to get the title.
The female protagonist finds someone online, I'm pretty sure with the exact name as her or something else that they share freakily in common. Her and her male best friend both agree to meet this online girl (at a train station perhaps?) and when they do meet they see that they are identical looking (the other girl wears strange adult clothes though).
When the two touch hands the main character is transported to the identical girl's parallel universe, which is like earth but slightly different. People she meets think she is the other girl, and treat her as such. An identical alternate version of her male best friend is also there, though the two are not friends in this universe (he works with her, and in the beginning dislikes her).
Shenanigans ensue and she gets in trouble a few times as she doesn't know the proper customs of the world, and it becomes increasingly clear that her alternate-self was a shady character that had some dealings with gangs or other underground business. A romance between the girl and her alternate best friend version occurs throughout.
Eventually they figure out a way to get her back home to her world, and the two girls swap back.
I think the title had a silhouette of a running girl on it, perhaps some shadows or curly images, and maybe a clock? I don't really remember...

Any help would be appreciated so so much!

[Ann aka Iftcan]

What genre Gracie? YA, adult, chapter book? Was there anything magical in the other world (other than the transfer between the 2 worlds.)

[Mir]

Shadow Web?

[Gracie]

that's it! oh my god thank you so much, I've been looking for it for months

[Mir]

Great! I really want to read it, too.